Flow box for paper machines



March 25, 1930. E. .1. TRIMBEY ET AL FLOW BOX FOR PAPER MACHINES FiledMay l5, 1929 M @Mw if m Mm w n Y., BM 0f Patented. Mar. 2.5, 1930 UNITEDSTATES PATENT 4OFFICE EDWARD J. TRIMBEY ANZI)V GEORGE K. WALKER, OEGLENS FALLS, NEW YORK FLOW BOX FOR PAPER MACHINES Application led May15,

This invention has to do with improvements in means for securinguniformity of iow as the liquid paper-making material flows out onto themoving wire of a Fourdrinier paper machine.

In the early days of paper making when the output of paper machines wasrelatively small it was comparatively easy to secure a smooth .evendistribution of the flow of thin liquid pulp as it went to the papermachine wire due to the fact that the width of the wire was only a fewfeet and the volume of liquid to be distributed was small. With theincrease in the width of the wires and the volumes of liquid pulphandled this became more of a problem and from time to time improvementswere made in the design of head boxes containing various arrangements ofbaffles,

dams with openings cut through them, small revolving paddle wheelsentirely submerged in the liquid, perforated revolving cylindersentirely submerged in the liquid, etc.

At the present time the accepted practice is to make use of a largerectangular head box whose width is approximately that of the wire andwhose length and depth are from one third to two thirds the width. Inthese head boxes are generally located from three to five verticalbaiiies or partitions extending alternately from the top to Within ashort distance of the bottom and from the bottom to approximately thelevel of the breast roll or apron, thus introducing many square feet ofsurface for the accumulation of slime which sooneror later becomesloosened and, passing over the wire and presses, adheres to the pressrolls or felts and causes frequent breaks of the sheet with consequentloss of production and deterioration of quality.

As mentioned before the purpose of these baiiies, etc. is to insure asmooth even flow of the liquid onto the wire so that the resulting sheetof paper will be of uniform thickness and will be uniformly dried. O-naccountof the high speeds employed, however, and the "per inch of Width1929. Serial No. 363,120.

large volumes of liquid pulp handled, the flow is not uniform at alltimes across the entire width of the wire; cross currents and eddies areformed, and at a given instant there will be considerably more pulppassing out at one point on the Wire than at adjacent points, while afewseconds later these currents will have changed and likewise theuniformity and thickness of the sheet of paper being produced.

The object of the present invention is to overcome these difficultiesand obtain a more uniform flow of pulp onto the wire with a resultingimprovement in the quality of the paper produced. In attaining thisobject we very greatly reduce the area of surface in contact with theliquid pulp as it flows from the screens to the breast roll of the papermachine by substituting for the long and deep rectangular head box, withits several baffles or partitions, a short shallow spout containing arevoluble blade-carrying member extending horizontally across they widthof the spout. The blades or plates o f'this member dip successively intothe flowing pulp as they are moved forward by the pulp stream and intheir passage extend across the path of flow. This at once eliminatesthe greater portion of the slime accumulating surface, and reduces thenumber of breaks with consequent increase in production and quality; atthe same time it completely eliminates cross currents and eddies andallows the liquid pulp to flow out from .the slice hand onto the wireevenly and uniformly. distributed, thus further improving the quality ofthe paper and the safe running of -the machine.

In the accompanying drawings 1n wlnch we have illustrated a preferredembodiment of our invention, Figure l is a vertical section through thespout and wheel of the present invention, taken along the line of flow;and Figure 2 is a section taken along line 2-2 of Figure 1.

In these drawings 1 represents the short shallow flow box or spoutlocated between the screens and the breast roll 2 and terminatingadjacent the wire in a slice 3. In this spout is located a paddle wheel4, mounted in suitable bearings 5, which are open at the top for theready removal of the paddle wheel. This wheel consists o f a bronze orother suitable noncorrosive shaft 6 carrying spiders 7 to Which areattached arms 8 carrying radial blades or plates 9 of thin metal.Attached to the outer edge of these plates 9 are flexible rubber'st-rips10. The bearings are bolted to the sides of the flow box or spout l atsuch a height that the outer edges of the flexible strips 10 just clearor drag slightly over the bottom of the spout. At a point directlybeneath the bearings the bottom of the box is made in the form of acylindrical section 11 concentric with the wheel, the chord of which isequal to or slightly greater than the chord across the tips of twoadjacent blades as extended by the addition of the strips l0. Since theblades 9 extend entirely across the spout 1 and their width is such thatthey extend at least as high as the surface of the flowing stream ofliquid pulp it is evident that except for a relatively small amount ofleakage, the liquid pulp from the screens can pass to the slice andbreast roll only as the paddle wheel revolves, and since the paddlewheel` is of light construction and freely mounted in the bearings thepressure of the flowing current will cause it to revolve at such a rateas to cause no objectionable hindrance to the flow of the liquid pulp.At the same time it is plainly evident that a swiftly moving current atone point across the width of the spout cannot pass directly to theslice but is held back by the blades 9, its energy distributed to theneighboring particles; andas the wheel revolves there is transferredfrom one end of the spout to the other a sectoral volume of liquid fromwhich all cross currents have been completely smoothed out andeliminated. This liquid will then pass out quietly and uniformly frombeneath the slice onto the moving wire and a uniform sheet of paper willbe produced.

By the use of the cylindrical section 11, or

by lowering the center of the shaft to a point where the flexible strips10 will bend and draw over the flat bottom surface, it follows that oneof the blades is always in position to prevent the free flow of thedisturbing currents; one blade and its flexible tip moving into positionin conjunction with the vsection 11 or the bottom of the spout, beforethe preceding tip ceases to register.

As illustrated in Figure l the flexible strips 8 bend due totheir ownweight so that as they leave the surface of the flowing stream of liquidpulp they are substantially normal to the surface, thus preventing thesetting up of any wave or disturbance due to the emergence of the bladesfrom the liquid. l -In the prising a plurality of plates movable in suclcession across the path of the flowing pulp by the movement of the pulpitself.

2. A flow box for paper machines comprising a plurality of platesmovable in succession across the path of the flowing pulp by themovement of the pulp ritself, the spacing between the plates being suchthat any given plate contacts with the bottom of the box before thenextpreceding plate moves out of contact. j

3. In a flow box for paper machines the combination of a rotatablemember extendin across the box, radial plates of a width equa to atleast the depth of t-he pulp in the box carried by said member, andmovable into and out of the pulp by the movement of the pulp stream.

4. In a flow box for paper machines the combination of a rotatablepaddle wheel extending across the box transversely of the path of flowand journaled above the pulp level, radial plates of a width equal to atleast the depth of thepulp in the box carried by the paddle wheel andcontacting in succession with the bottom of the box as the wheel isrotated.Y

5. In a flow box for paper machines the combination of a rotatablepaddle wheel extending across the box transversely of the path of flowand journaled above the pulp level, radial plates of a width equal to atleast the depth of the pulpin the box carried by the paddle wheel andflexible edges on said plates the spacing between the plates being suchthat the flexible edge of any given plate contacts with the bottom ofthe box before the edge of the next preceding plate moves vided withplates which successively pass through the pulp stream as the wheelrotates, and a cylindrical section in the bottom of the boxconcentricwithand below the wheel and of such dimensions that as thewheel rotates, each plate contacts with the cylindricalsection beforethe next preceding plate moves out of contact therewith.

8. Means for eliminating cross currents...

